没有想到speex还在持续的更新 - c6000
听说微信改用了speex, 于是今天访问了speex网站:
发现从08年的Speex 1.2rc1之后,在2014年12月份和2015年1月份更新了两次
根据说明,是说对resampler做了NEON指令的优化,我记得案桌里面就带有speex的resampler的NEON版本(不过还是不如我们自己优化的快),不知道为什么speex.org刚刚更新。
每个codec都宣称自己很好,比如speex说:
Speex is based on CELP and is designed to compress voice at bitrates ranging from 2 to 44 kbps. Some of Speex's features include:
- Narrowband (8 kHz), wideband (16 kHz), and ultra-wideband (32 kHz) compression in the same bitstream
- Intensity stereo encoding
- Packet loss concealment
- Variable bitrate operation (VBR)
- Voice Activity Detection (VAD)
- Discontinuous Transmission (DTX)
- Fixed-point port
- Acoustic echo canceller
- Noise suppression
Note that Speex has a number of features that are not present in other codecs, such as intensity stereo encoding, integration of multiple sampling rates in the same bitstream (embedded coding), and a VBR mode; see our comparison page for more.
对于speex 1.2 rc1的说明是:
This release adds support for acoustic echo cancellation with multiple microphones and multiple loudspeakers. It also adds an API to decorrelate loudspeaker signals to improve multi-channel performance. In the bugfix department, there are fixes for a few bugs in the echo canceller, jitter buffer and preprocessor. At this point, the API for 1.2 should be stable and only a few very minor additions are planned
是支持双麦克回声抵消么? 很想测测看效果怎么样。。
不知道和后来的codec比,比如SILK, OPUS, EVS之间的效果怎么样?
需要比较一下么?
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